1. Technical Field
The present invention relates to a light source apparatus equipped with a discharge lamp having a pair of electrodes, and a drive method thereof, as well as a projector in which such a light source apparatus is embedded.
2. Related Art
An electrode of an ultra-high pressure mercury lamp embedded in a discharge light emitting type light source apparatus erodes as a lit time elapses, a length and a position of an arc changes, and an origin of a discharge is not stable in one place, causing a flicker. In order to remedy this, a technology of smoothing out a surface and newly forming a projection thereon, by temporarily making a current magnitude larger at a steady time and fusing an electrode leading extremity, has been known (refer to Japanese Patent No. 3840054).
However, when changing a current value during a lighting operation with a steady power, as an illuminance of a light source changes along with it, a brightness of a projection image changes, and there is a danger of having an adverse effect on a performance as a video instrument. Also, the electrode leading extremity being of a comparatively normal shape at a stage at which an aging has not progressed too far, carrying out the fusion of the electrode leading extremity at this time results in making the arc length unnecessarily long.